Piezoelectric properties of lead-free Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics from nanopowders
Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) ceramics were obtained from nanometric powder synthesized by sol gel auto-combustion at 500ºC. Hot-pressing at low temperatures and a combination of this with re-crystallization, still moderate in order to reduce loss of the volatile elements,...
| Autores: | , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/40316 |
| Acesso em linha: | http://hdl.handle.net/10261/40316 |
| Access Level: | acceso abierto |
| Palavra-chave: | Piezoelectric Piezoelectrica Ceramic Cerámica Lead-free Verde Microstructure Microestructura Nanopowder Nanopartícula Ferroelectric Ferroeléctrica Dielectric Dieléctrica Structure Estructura |
| Resumo: | Submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBT6) ceramics were obtained from nanometric powder synthesized by sol gel auto-combustion at 500ºC. Hot-pressing at low temperatures and a combination of this with re-crystallization, still moderate in order to reduce loss of the volatile elements, have been tested. Material properties, including all losses, were determined at the resonances of thin disks using Alemany et al. software. Ceramics hot pressed at 700-800ºC for 2h have a pseudo-cubic structure, grain size of few hundreds of nanometers and are homogeneous. Both their crystal structure and the lack of sintering prevent their poling. For ceramics hot-pressed at 950ºC for 3h, Bi or (Bi0.5Na0.5) loss, together with low piezoelectric properties (d33=60 pC.N-1, kp=8%), was observed. Re-crystallization at 1000ºC-1h of ceramics hot-pressed at 700 and 800ºC for 2h keeps submicron-structure, reduces porosity and prevents off-stoichiometry. Mechanical and piezoelectric losses are also reduced and coupling factors increased (kp=24.6%, kt=36.4%). The best piezoelectric coefficient obtained in these ceramics (d33=143 pC.N-1) is comparable with those reported for coarse-grained ceramics |
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